U.S. patent application number 13/687017 was filed with the patent office on 2013-04-18 for power recovery device of liquid processing apparatus.
The applicant listed for this patent is Koichi Matsui, Ryoichi Takahashi. Invention is credited to Koichi Matsui, Ryoichi Takahashi.
Application Number | 20130094949 13/687017 |
Document ID | / |
Family ID | 45066282 |
Filed Date | 2013-04-18 |
United States Patent
Application |
20130094949 |
Kind Code |
A1 |
Takahashi; Ryoichi ; et
al. |
April 18, 2013 |
POWER RECOVERY DEVICE OF LIQUID PROCESSING APPARATUS
Abstract
According to one embodiment, a power recovery device is used in
an apparatus in which firstly pressurized raw water (FPRW) is
supplied to a reverse osmosis membrane unit to extract fresh water
and condensed and depressurized raw water (HPB) remains. The device
recovers the energy of HPB, rises a pressure of raw water (LPF) by
using the recovered energy, and adds such secondly pressurized raw
water (HPF) to the FPRW. The device accommodates a fixed center
shaft and a rotary member on the shaft in a housing. LPF flows into
one paired chambers of the housing and radial channels of the
member to push and rotate the member, and HPB is introduced into
the channels through paired openings of the shaft to push out LPF
as HPF from the channels and another paired chambers of the
housing.
Inventors: |
Takahashi; Ryoichi;
(Yokohama-shi, JP) ; Matsui; Koichi; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Takahashi; Ryoichi
Matsui; Koichi |
Yokohama-shi
Tokyo |
|
JP
JP |
|
|
Family ID: |
45066282 |
Appl. No.: |
13/687017 |
Filed: |
November 28, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2010/059220 |
May 31, 2010 |
|
|
|
13687017 |
|
|
|
|
Current U.S.
Class: |
415/185 |
Current CPC
Class: |
Y02B 10/50 20130101;
F05B 2220/60 20130101; F05B 2220/602 20130101; F03B 13/00 20130101;
F01D 5/02 20130101 |
Class at
Publication: |
415/185 |
International
Class: |
F01D 5/02 20060101
F01D005/02 |
Claims
1. A power recovery device which is used in a liquid processing
apparatus in which raw water as externally supplied water
containing a plurality of components is supplied to a reverse
osmosis membrane through a pressure raising unit and extracts a
part of fresh water from the pressure raised raw water by the
reverse osmosis membrane, and which supplies raw water a pressure
of which is raised by using a pressure of remaining raw water from
which the part of the fresh water is extracted by the reverse
osmosis membrane to the reverse osmosis membrane, in addition to
the pressure raised raw water from the pressure raising unit, the
power recovery device comprising: a housing having an internal
space; a center shaft fixed in the internal space of the housing
and having an outer circumferential surface and at least one end
portion protruding outside the housing; and a rotary member
accommodated in the internal space of the housing such that the
rotary member is rotatable on the outer circumferential surface of
the center shaft, having an inner circumferential surface opposing
the outer circumferential surface of the center shaft and an outer
circumferential surface positioned outside the center shaft in a
radial direction of the center shaft, and including a plurality of
channels arranged at equal intervals in a circumferential direction
of the center shaft and each extending between the inner
circumferential surface thereof and the outer circumferential
surface thereof, wherein at least one set of two pairs of chambers
opposing the outer circumferential surface of the rotary member and
divided from each other is provided in the internal space of the
housing, at least one set of two pairs of openings opening in the
outer circumferential surface of the center shaft to be equal in
number to the chambers to oppose the at least one set of the
chambers in the internal space of the housing through the rotary
member, and at least one set of two pairs of passages extending
through the center shaft from the at least one set of the openings
and opening in the at least one end portion of the center shaft,
are formed in the center shaft, one pair of the chambers
symmetrically arranged with respect to the center shaft in the one
set of the chambers in the internal space of the housing is
configured to be introduced with the externally supplied raw water
and to cause the externally supplied raw water to push the
plurality of channels in the outer circumferential surface of the
rotary member exposed in the one pair of chambers, in a
predetermined circumferential direction of the outer
circumferential surface so as to rotate the rotary member, the
other pair of the chambers symmetrically arranged with respect to
the center shaft in the one set of the chambers is connected to a
channel of the pressure raised raw water between the pressure
raising unit and the reverse osmosis membrane, one pair of the
openings of the one set of openings in the outer circumferential
surface of the center shaft, opposing the one pair of the chambers
through the rotary member are communicated with an outside through
one pair of the passages corresponding to the one pair of the
openings in the center shaft, and the other pair of the openings of
the one set of the openings in the outer circumferential surface of
the center shaft, opposing the other pair of the chambers through
the rotary member is introduced with the remaining raw water
through the other pair of the passages corresponding to the other
pair of the openings in the center shaft.
2. The power recovery device according to claim 1, wherein the
center shaft is long and narrow, and has another end portion
protruding outside the housing in a side opposite to the one end
portion along a longitudinal central line of the center shaft, the
one pair of the passages of the center shaft opens in the one end
portion of the center shaft, and the other pair of the passages of
the center shaft opens in the other end portion of the center
shaft.
3. The power recovery device according to claim 1, wherein the
center shaft is long and narrow, and has another end portion
positioned in a side opposite to the one end portion along a
longitudinal central line of the center shaft, and accommodated in
the internal space of the housing.
4. The power recovery device according to claim 1, further
comprises an electric motor including an output shaft which is
connected to the rotary member and rotates together with the rotary
member.
5. The power recovery device according to claim 1, wherein the raw
water is salt water.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation Application of PCT
Application No. PCT/JP2010/059220, filed May 31, 2010, the entire
contents of which are incorporated herein by reference.
FIELD
[0002] Embodiments described herein relate generally to a power
recovery device of a liquid processing apparatus.
BACKGROUND
[0003] A liquid processing apparatus which processes water
containing a plurality of components (to be referred to as raw
water hereinafter) by using a reverse osmosis membrane called,
e.g., an RO membrane is known.
[0004] The raw water is supplied to the reverse osmosis membrane at
a high pressure, and fresh water is extracted from the raw water by
the reverse osmosis membrane. In this process, a ratio of fresh
water extracted by the reverse osmosis membrane rises as a value of
the pressure of the raw water supplied to the reverse osmosis
membrane rises. To raise the pressure value of the raw water,
however, it is necessary to increase a strength of a raw water
pressure raising device which is necessary to raise the pressure
value of the raw water, and an amount of energy required to
increase the pressure of the raw water also increases. In addition,
a structure of the raw water pressure raising device is normally
complicated.
[0005] Raw water from which the fresh water is extracted at a given
ratio by the reverse osmosis membrane (to be referred to as
high-concentration raw water hereinafter) loses its pressure more
or less because the fresh water is extracted by the reverse osmosis
membrane. However, the high-concentration raw water maintains most
of the high pressure loaded on the raw water when supplied to the
reverse osmosis membrane.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a view schematically showing the whole of one
example of a liquid processing apparatus in which a power recovery
device according to a first embodiment.
[0007] FIG. 2 is a perspective view schematically showing an outer
appearance of the power recovery device according to the first
embodiment.
[0008] FIG. 3 is a schematic exploded perspective view of the power
recovery device of FIG. 2.
[0009] FIG. 4 is a schematic perspective view showing, from below,
a case including a center shaft of the power recovery device of
FIG. 3.
[0010] FIG. 5 is a schematic perspective view showing a horizontal
section of a rotary member of the power recovery device of FIG.
3.
[0011] FIG. 6 is a schematic perspective view of the center shaft
of the power recovery device of FIG. 3.
[0012] FIG. 7 is a schematic perspective view of a lower portion of
the center shaft of FIG. 6, after the center shaft is cut along a
line IIV-IIV.
[0013] FIG. 8 is an exploded perspective view similar to FIG. 3,
for explaining an operation of the power recovery device of FIG.
2.
[0014] FIG. 9 is a schematic plan view of a combination of the
case, center shaft, and rotary member of FIG. 8, for explaining the
operation of the power recovery device of FIG. 2.
[0015] FIG. 10 is a schematic exploded perspective view of a power
recovery device according to a second embodiment.
[0016] FIG. 11 is a perspective view showing a rotary member of the
power recovery device of FIG. 10, with a half of the rotary member
being horizontally cut.
[0017] FIG. 12 is a perspective view of a center shaft of FIG.
10.
[0018] FIG. 13 is a schematic perspective view of a lower portion
of the center shaft shown of FIG. 12, after the center shaft is cut
along a line XIII-XIII.
[0019] FIG. 14 is a schematic perspective view of a lower end part
portion of the lower portion of the center shaft of FIG. 13, after
the lower portion is further cut along a line XIV-XIV.
DETAILED DESCRIPTION
[0020] A power recovery device of a liquid processing apparatus,
according to an embodiment is a power recovery device which is used
in a liquid processing apparatus in which raw water as externally
supplied water containing a plurality of components is supplied to
a reverse osmosis membrane through a pressure raising unit and
extracts a part of fresh water from the pressure raised raw water
by the reverse osmosis membrane, and which supplies raw water a
pressure of which is raised by using a pressure of remaining raw
water from which the part of the fresh water is extracted by the
reverse osmosis membrane to the reverse osmosis membrane, in
addition to the pressure raised raw water from the pressure raising
unit.
[0021] The power recovery device comprises: a housing having an
internal space; a center shaft fixed in the internal space of the
housing and having an outer circumferential surface and at least
one end portion protruding outside the housing; and a rotary member
accommodated in the internal space of the housing such that the
rotary member is rotatable on the outer circumferential surface of
the center shaft, having an inner circumferential surface opposing
the outer circumferential surface of the center shaft and an outer
circumferential surface positioned outside the center shaft in a
radial direction of the center shaft, and including a plurality of
channels arranged at equal intervals in a circumferential direction
of the center shaft and each extending between the inner
circumferential surface thereof and the outer circumferential
surface thereof.
[0022] At least one set of two pairs of chambers opposing the outer
circumferential surface of the rotary member and divided from each
other is provided in the internal space of the housing.
[0023] At least one set of two pairs of openings opening in the
outer circumferential surface of the center shaft to be equal in
number to the chambers to oppose the at least one set of the
chambers in the internal space of the housing through the rotary
member, and at least one set of two pairs of passages extending
through the center shaft from the at least one set of the openings
and opening in the at least one end portion of the center shaft,
are formed in the center shaft.
[0024] One pair of the chambers symmetrically arranged with respect
to the center shaft in the one set of the chambers in the internal
space of the housing is configured to be introduced with the
externally supplied raw water and to cause the externally supplied
raw water to push the plurality of channels in the outer
circumferential surface of the rotary member exposed in the one
pair of chambers, in a predetermined circumferential direction of
the outer circumferential surface so as to rotate the rotary
member.
[0025] The other pair of the chambers symmetrically arranged with
respect to the center shaft in the one set of the chambers is
connected to a channel of the raw water between the pressure
raising unit and the reverse osmosis membrane.
[0026] One pair of the openings of the one set of the openings in
the outer circumferential surface of the center shaft, opposing the
one pair of the chambers through the rotary member are communicated
with an outside through one pair of the passages corresponding to
the one pair of the openings in the center shaft.
[0027] The other pair of the openings of the one set of the
openings in the outer circumferential surface of the center shaft,
opposing the other pair of the chambers through the rotary member
is introduced with the remaining raw water through the other pair
of the passages corresponding to the other pair of the openings in
the center shaft.
[0028] First of all, a schematic structure of the whole of an
example of a liquid processing apparatus in which a power recovery
device according to a first embodiment will be explained with
reference to FIG. 1.
[0029] The liquid processing apparatus of the example is a seawater
desalination apparatus. In this seawater desalination apparatus,
raw water as externally supplied water containing a plurality of
components is seawater. Seawater SW pumped up from the sea is
supplied to a preprocessing unit 10. The preprocessing unit 10
preprocesses the supplied seawater SW by adding, e.g., a germicide
10a, flocculant 10b, scale inhibitor 10c, dechlorine agent 10d,
etc. to the seawater SW. Seawater (preprocessed seawater) PSW which
is preprocessed is led to pass through a water supply pump 12 and
safety filter 14 by a pipe. The preprocessed seawater PSW passed
through the safety filter 14 is branched into two parts by branched
pipes.
[0030] One branched pipe is connected to a reverse osmosis membrane
unit 18 containing a reverse osmosis membrane 18a through a
pressure raising unit 16. In this example, the pressure raising
unit 16 is provided by a high-pressure pump. The preprocessed
seawater PSW on which a predetermined high pressure is loaded by
the pressure raising unit 16 is supplied to the reverse osmosis
membrane unit 18 by the one branched pipe. In the reverse osmosis
membrane unit 18, the reverse osmosis membrane 18a extracts a part
of water (fresh water) FW from the high-pressure preprocessed
seawater HPSW.
[0031] The extracted water FW is led to a clear water tank 20 by a
pipe. In the clear water tank 20, clear water CW is produced by
adding, e.g., a hardness control agent 20a, pH adjuster 20b,
disinfectant 20c, etc. to the water FW. The clear water CW produced
in the clear water tank 20 is supplied to a water pipe 23 through a
clear water supply pump 22.
[0032] The other branched pipe is connected to the power recovery
device 24 according to the first embodiment.
[0033] The low-pressure preprocessed seawater PSW to be supplied to
the power recovery device 24 through the other branched pipe is
called as low-pressure feed LPF. Seawater (high-concentration
seawater) in which concentrations of the various components
including salt are increased because a part of the water FW is
extracted by the reverse osmosis membrane unit 18 and the pressure
is more or less decreased, is led to the power recovery device 24
through a pipe. This high-concentration seawater supplied from the
reverse osmosis membrane unit 18 to the power recovery device 24 is
called as high-pressure brine HPB.
[0034] In the power recovery device 24, a pressure of the
high-pressure brine HPB is raised by the energy of the low-pressure
feed LPF, and then the high-pressure brine HPB the pressure of
which is raised pushes the low-pressure feed LPF and raises a
pressure of the low-pressure feed LPF, and finally high-pressure
feed HPF is discharged. That is, the energy of the high-pressure
feed HPF is generated by using most of the energy of the
high-pressure brine HPB, and by adding a part of the energy of the
low-pressure feed LPF.
[0035] The high-pressure feed HPF is led by a pipe from the power
recovery device 24 to a pipe between the pressure raising unit 16
and the reverse osmosis membrane unit 18. In this pipe, the
high-pressure feed HPF is added to the high-pressure preprocessed
seawater HPSW flowing from the pressure raising unit 16 to the
reverse osmosis membrane unit 18, and flows together with the
high-pressure preprocessed seawater HPSW toward the reverse osmosis
membrane unit 18.
[0036] In the power recovery device 24, the low-pressure feed LPF
used to raise the pressure of the high-pressure brine HPB becomes
the high-pressure feed HPF in a next stage in which the pressure of
the low-pressure feed LPF is raised by the high-pressure brine HPB
whose pressure is further raised by using a part of the energy of
the low-pressure feed LPF. After raising the pressure of the
low-pressure feed LPF, the high-pressure brine HPB loses its
pressure and is discharged outside as low-pressure brine LPB from
the power recovery device 24.
First Embodiment
[0037] Next, a structure of the power recovery device 24 of the
first embodiment will be explained with reference to FIGS. 2-7.
[0038] As shown in FIGS. 2-4, the power recovery device 24
comprises a housing 32 having an internal space 30. In this
embodiment, the housing 32 includes a case 32a having an almost
circular recess that provides the internal space 30, and a lid 32b
that liquid-tightly covers one opening of the recess of the case
32a. The lid 32b is detachably fixed to the case 32a by a
well-known fixing means (not shown).
[0039] The power recovery device 24 further comprises a center
shaft 34 fixed in the internal space 30 of the housing 32, and
having an outer circumferential surface and at least one end
portion protruding outside the housing 32. More specifically, the
center shaft 34 is long and narrow, and a portion of its outer
circumferential surface is liquid-tightly fixed in a through hole
32c formed in a center of a bottom surface of the recess of the
case 32a. The One end portion of the center shaft 34 is positioned
at one end along a longitudinal central line of the center shaft 34
and protrudes from the through hole 32c into an external space
below the case 32a. The other end portion of the center shaft 34 is
positioned at the other end along the longitudinal central line and
protrudes from a through hole 32d in a center of the lid 32b into
the external space above the lid 32b.
[0040] The power recovery device 24 further comprises a rotary
member 36 accommodated in the internal space 30 of the housing 32
so as to be rotatable on the outer circumferential surface of the
center shaft 34. The rotary member 36 includes an inner
circumferential surface 36a opposing the outer circumferential
surface of the center shaft 34, and an outer circumferential
surface 36b positioned outside in a radial direction of the center
shaft 34. As is well shown in FIG. 5, the rotary member 36 further
includes a plurality of channels 36c arranged at equal intervals in
a circumferential direction of the center shaft 34 and each
extending between the inner circumferential surface 36a and the
outer circumferential surface 36b.
[0041] As is well shown in FIG. 3, at least one set of two pairs of
chambers 38a and 38b opposing the outer circumferential surface 36b
of the rotary member 36 and divided from each other is provided in
the internal space 30 of the housing 32. In this embodiment, one
set of two pairs of the chambers 38a and 38b is provided.
[0042] The low-pressure feed LPF supplied to the power recovery
device 24 as shown in FIG. 1 is led, as shown in FIG. 2, into one
pair of the chambers 38a, 38a symmetrically arranged with respect
to the center shaft 34 in the one set of the chambers 38a and 38b
in the internal space 30 of the housing 32. The one pair of the
chambers 38a, 38a are configured such that the supplied
low-pressure feed LPF flows along the outer circumferential surface
36b of the rotary member 36, which is exposed in the one pair of
the chambers 38a, 38a in a predetermined circumferential direction
(in FIG. 3, in a counterclockwise direction) of the outer
circumferential surface 36b.
[0043] The other paired chambers 38b, 38b of the one set of the
chambers 38a and 38b, symmetrically arranged with respect to the
center shaft 34, are connected to the pipe for the high-pressure
feed HPF extending from the power recovery device 24 toward the
pipe between the pressure raising unit 16 and the reverse osmosis
membrane unit 18 as shown in FIGS. 1 and 2.
[0044] As is well shown in FIGS. 6 and 7, at least one set of two
pairs of openings 40a and 40b equal in number to the at least one
set of the chambers 38a and 38b in the internal space 30 of the
housing 32 is formed in the outer circumferential surface of the
center shaft 34 so as to oppose the chambers 38a and 38b through
the rotary member 36. In this embodiment, one set of the two pairs
of the openings 40a and 40b is formed in the outer circumferential
surface of the center shaft 34 so that the openings 40a and 40b are
arranged at equal intervals in a circumferential direction of the
outer circumferential surface.
[0045] One pair of passages 42a, 42a (see FIG. 7) extends through
the center shaft 34 from the one pair of the openings 40a, 40a
corresponding to the one pair of the chambers 38a, 38a in the
internal space 30 of the housing 32 to the other end portion of the
center shaft 34, which is positioned upwardly in FIG. 6, and the
pair of passages 42a, 42a is opened at an end surface of the other
end portion. As shown in FIGS. 2, 3, and 6, the paired passages
42a, 42a can be integrated into one passage 42a in the center shaft
34 before they reach the other end portion. As shown in FIGS. 1 and
2, the opening of the integrated passage 42a in the end surface of
the other end portion of the center shaft 34 is connected to a pipe
for the low-pressure brine LPB, which extends from the power
recovery device 24.
[0046] Another pair of passages 42b, 42b (see FIG. 7) extends
through the center shaft 34 from the other pair of the openings
40b, 40b corresponding to the other pair of the chambers 38b, 38b
in the internal space 30 of the housing 32 to the one end portion
of the center shaft 34, which is positioned downwardly in FIG. 6,
and opens at an end surface of the one end portion. As shown in
FIG. 4, the paired passages 42b, 42b can be integrated into one
passage 42b in the center shaft 34 before they reach the one end
portion. As shown in FIGS. 1 and 2, the opening of the integrated
passage 42b in the end surface of the one end portion of the center
shaft 34 is connected to the pipe for the high-pressure brine HPB,
which extends from the reverse osmosis membrane unit 18 to the
power recovery device 24.
[0047] Next, an operation of the power recovery device 24 described
above with reference to FIGS. 2-7 will now be explained with
reference to FIGS. 8 and 9.
[0048] As shown in FIGS. 8 and 9, the high-pressure brine HPB
supplied from the reverse osmosis membrane unit 18 shown in FIG. 1
to the power recovery device 24 reaches the paired openings 40b,
40b in the outer circumferential surface of the center shaft 34
through the passage 42b (see FIG. 4) opened in the end surface of
the downward one end portion of the center shaft 34 of the power
recovery device 24, and flows into several channels 36c inner ends
of which are exposed to the other paired openings 40b, 40b among
the plurality of channels 36c of the rotary member 36. Meanwhile,
as shown in FIGS. 8 and 9, the low-pressure feed LPF supplied from
the preprocessing unit 10 shown in FIG. 1 to the power recovery
device 24 through the water supply pump 12 and safety filter 14
flows into the one pair of the chambers 38a, 38a of the case 32a of
the housing 32 of the power recovery device 24. The low-pressure
feed LPF flowed into the one pair of the chambers 38a, 38a pushes
parts of the outer circumferential surface of the rotary member 36,
which are exposed in the one pair of the chambers 38a, 38a, in a
predetermined circumferential direction of the outer
circumferential surface of the rotary member 36. As a result, the
low-pressure feed LPF in the one pair of the chambers 38a, 38a
flows into several channels 36c outer ends of which are exposed to
the one pair of the chambers 38a, 38a among the plurality of
channels 36c of the rotary member 36, and pushes side surfaces of
the several channels 36c. A part of energy of the low-pressure feed
LPF is consumed to rotate the rotary member 36 in a predetermined
direction R.
[0049] As the rotary member 36 rotates, the low-pressure feed LPF
in the channels 36c is held in the channels 36c between the one
pair of the chambers 38a, 38a and the other pair of the chambers
38b, 38b and between the one pair of the openings 40a, 40a and the
other pair of the openings 40b, 40b of the center shaft 34. When
the channels 36c holding the low-pressure feed LPF oppose the other
pair of the chambers 38b, 38b and the other pair of the openings
40b, 40b of the center shaft 34, the low-pressure feed LPF held in
the channels 36c is pushed out from the channels 36c into the other
pair of the chambers 38b, 38b by the high-pressure brine HPB flowed
from the other pair of the openings 40b, 40b into the channels 36c
holding the low-pressure feed LPF. During this action, the pressure
energy of the high-pressure brine HPB flowed from the openings 40b,
40b into the channels 36c is given to the low-pressure feed LPF
held in the channels 36c, so that the low-pressure feed LPF held in
the channels 36 becomes the high-pressure feed HPF and is pushed
into the other pair of the chambers 38b, 38b.
[0050] The high-pressure brine HPB flowed into the channels 36c
from the other pair of the openings 40b, 40b becomes the
low-pressure brine LPB because the high-pressure brine HPB gives
its pressure energy to the low-pressure feed LPF in the channels
36c and its pressure energy is largely decreased or eliminated.
After that, further rotation of the rotary member 36 makes the
low-pressure brine LPB being held in the channels 36c between the
other pair of the chambers 38b, 38b and the one pair of the
chambers 38a, 38a and between the other pair of the openings 40b,
40b and the one pair of the openings 40a, 40a of the center shaft
34. And then, when the channels 36c holding the low-pressure brine
LPB oppose the one pair of the chambers 38a, 38a and the one pair
of the openings 40a, 40a of the center shaft 34, the low-pressure
feed LPF is flowed from the one pair of the chambers 38a, 38a into
the channels 36c holding the low-pressure brine LPB so that the
low-pressure brine LPB in the channels 36c is discharged out from
the power recovery device 24 through the one pair of the openings
40a, 40a and the one pair of the passages 42a, 42a corresponding to
the one pair of the openings 40a, 40a.
[0051] As shown in FIG. 1, the high-pressure feed HPF in the other
pair of the chambers 38b, 38b is led by the pipe from the power
recovery device 24 to the pipe between the pressure raising unit 16
and the reverse osmosis membrane unit 18. In the latter pipe, the
high-pressure feed HPF is added to the high-pressure preprocessed
seawater HPSW flowing from the pressure raising unit 16 toward the
reverse osmosis membrane unit 18, and flows together with the
high-pressure preprocessed seawater HPSW toward the reverse osmosis
membrane unit 18.
[0052] AS a result of this, if an amount of the fresh water FW
extracted in the reverse osmosis membrane unit 18 per unit time is
constant, it is possible to reduce an amount of the high-pressure
preprocessed seawater HPSW to be supplied from the pressure raising
unit 16 toward the reverse osmosis membrane unit 18 per unit time.
This makes it possible to reduce an amount of energy, i.e., power
necessary to operate the seawater desalination apparatus as a kind
of the liquid processing apparatus using the power recovery device
24.
[0053] In the power recovery device 24 of this embodiment, the one
set of the two pairs of the chambers 38a and 38b are provided to be
divided from each other in the internal space 30 of the case 32a of
the housing 32, and the same low-pressure feed LPF is supplied to
the one pair of the cambers 38a, 38a symmetrically arranged with
respect to the center shaft 34, and at the same time the same
high-pressure brine HPB is supplied toward the other pair of the
chambers 38b, 38b symmetrically arranged with respect to the center
shaft 34. Accordingly, a force loaded on the case 32a of the
housing 32 and a force loaded on the rotary member 36 accommodated
in the internal space 30 of the case 32a so as to be rotatable on
the outer circumferential surface of the center shaft 34, by the
low-pressure feed LPF in the one pair of the chambers 38a, 38a, are
canceled in the radial direction of the center shaft 34, and also a
force loaded on the case 32a and a force loaded on the rotary
member 36, by the high-pressure brine HPB in the other pair of the
chambers 38b, 38b, are canceled in the radial direction of the
center shaft 34.
[0054] Further, a mixture of the low-pressure brine LPB and
high-pressure brine HPB, entered into a gap between the outer
circumferential surface of the center shaft 34 and the inner
circumferential surface 36a of the rotary member 36 functions as a
radial dynamic pressure bearing between the outer circumferential
surface of the center shaft 34 and the inner circumferential
surface 36a of the rotary member 36 with a rotation of the rotary
member 36 on the outer circumferential surface of the center shaft
34. Also, a mixture of the low-pressure feed LPF and high-pressure
feed HPF, entered into gaps between the outer circumferential
surface 36b of the rotary member 36 and regions of an inner
circumferential surface of the internal space 30 of the case 32a of
the housing 32, the inner circumferential surface of the internal
space 30 opposing the outer circumferential surface 36b of the
rotary member 36 and the regions excepting the one set of the two
pairs of the chambers 38a and 38b, functions as a radial dynamic
pressure bearing between the outer circumferential surface 36b of
the rotary member 36 and the above-mentioned regions of the inner
circumferential surface of the internal space 30 of the case 32a of
the housing 32 with the rotation of the rotary member 36 on the
outer circumferential surface of the center shaft 34.
[0055] Therefore, there is no need for an independent radial
bearing between the outer circumferential surface of the center
shaft 34 and the inner circumferential surface 36a of the rotary
member 36, and it is possible to simplify the structure of the
power recovery device 24 of this embodiment and to reduce a
manufacturing cost thereof.
[0056] More further, a mixture of the low-pressure brine LPB and
high-pressure brine HPB and a mixture of the low-pressure feed LPF
and high-pressure feed HPF, both mixtures entered into a gap
between an inner surface of the lid 32b of the housing 32 and one
side surface of the rotary member 36, which opposes the
above-mentioned inner surface, in the internal space 30 of the case
32a of the housing 32, function as a thrust bearing between the
inner surface of the lid 32b and the one side surface of the rotary
member 36 with the rotation of the rotary member 36 on the outer
circumferential surface of the center shaft 34. Simultaneously, the
mixture of the low-pressure brine LPB and high-pressure brine HPB
and the mixture of the low-pressure feed LPF and high-pressure feed
HPF, both entered into a gap between the bottom surface of the
internal space 30 of the case 32a of the housing 32 and the other
side surface of the rotary member 36, which opposes the
above-mentioned bottom surface, in the internal space 30 of the
case 32a of the housing 32, function as a thrust bearing between
the bottom surface of the internal space 30 of the case 32a and the
other side surface of the rotary member 36 with the rotation of the
rotary member 36 on the outer circumferential surface of the center
shaft 34.
[0057] Therefore, there is no need for independent thrust bearings
between the inner surface of the lid 32b and the one side surface
of the rotary member 36 and between the bottom surface of the
internal space 30 of the case 32a and the other side surface of the
rotary member 36, and it is possible to simplify the structure of
the power recovery device 24 of this embodiment and to reduce the
manufacturing cost thereof.
Second Embodiment
[0058] Next, a structure of a power recovery device 24' according
to a second embodiment and being usable in the example of the
liquid processing apparatus described above with reference to FIG.
1, instead of the power recovery device 24 of the first embodiment
described above with reference to FIGS. 2-9, will be explained with
reference to FIGS. 10-14.
[0059] As shown in FIGS. 10-14, the power recovery device 24'
comprises a housing 43 having an internal space 41. In this
embodiment, the housing 43 includes a case 43a having an almost
circular recess that provides the internal space 41, and a lid 43b
that liquid-tightly covers an opening on one side of the recess of
the case 43a. The lid 43b is detachably fixed to the case 43a by a
well-known fixing means (not shown).
[0060] The power recovery device 24' comprises a center shaft 44
protruding from a center of the internal space 41 of the housing 43
into an external space above the lid 43b through a through hole 43c
in a center of the lid 43b. More specifically, the center shaft 44
is long and narrow, and a portion of its outer circumferential
surface is liquid-tightly fixed in the through hole 43c in the
center of the lid 43b. One end portion of the center shaft 44,
which is positioned at one end along a longitudinal central line of
the center shaft 44, protrudes from the through hole 43c of the lid
42b into the external space above the lid 43b. The other end
portion of the center shaft 44, which is positioned at the other
end along the longitudinal central line, is positioned slightly and
upwardly away from the center of the bottom surface of the internal
space 41 of the housing 43.
[0061] The power recovery device 24' further comprises a rotary
member 46 accommodated in the internal space 41 of the housing 43
so as to be rotatable on the outer circumferential surface of the
other end portion of the center shaft 44. More specifically, a
blind hole 46a for receiving the other end portion of the center
shaft 44 is formed in a center of the rotary member 46. An inner
circumferential surface 46b and bottom surface of the blind hole
46a relatively rotatably oppose the outer circumferential surface
and end surface of the other end portion of the center shaft 44
received in the blind hole 46a. The rotary member 46 includes an
outer circumferential surface 46c positioned outside the blind hole
46a in a radial direction thereof, and a plurality of channels 46d
arranged at equal intervals in a circumferential direction of the
blind hole 46a and each extending between the inner circumferential
surface 46b and the outer circumferential surface 46c as is well
shown in FIG. 11. As is well shown in FIG. 10, at least one set of
two pairs of chambers 48a and 48b opposing the outer
circumferential surface 46c of the rotary member 46 and divided
from each other is provided in the internal space 41 of the housing
43. In this embodiment, one set of the two pairs of the chambers
48a and 48b is provided.
[0062] As shown in FIG. 10, the low-pressure feed LPF supplied to
the power recovery device 24 shown in FIG. 1 is supplied to the one
pair of the chambers 48a, 48a symmetrically arranged with respect
to the center shaft 44 among the one set of the chambers 48a and
48b in the internal space 41 of the housing 43. The one pair of the
chambers 48a, 48a are configured to flow the supplied low-pressure
feed LPF along the outer circumferential surface 46c of the rotary
member 46 exposed in the one pair of the chambers 48a, 48a in a
predetermined circumferential direction (in FIG. 10, a
counterclockwise direction) of the outer circumferential surface
46c.
[0063] As shown in FIGS. 1 and 10, the other pair of the chambers
48b, 48b symmetrically arranged with respect to the center shaft 44
in the one set of the chambers 48a and 48b, is connected to the
pipe for the high-pressure feed HPF extending from the power
recovery device 24' toward the pipe between the pressure raising
unit 16 and reverse osmosis membrane unit 18.
[0064] As is well shown in FIGS. 10, and 12-14, at least one set of
two pairs of openings 50a and 50b equal in number to the at least
one set of the chambers 48a and 48b in the internal space 41 of the
housing 43 is formed in the outer circumferential surface of the
other end portion of the center shaft 44 so as to oppose the at
least one set of the chambers 48a and 48b through the rotary member
46. In this embodiment, one set of the two pairs of the openings
50a and 50b is formed in the outer circumferential surface of the
other end portion of the center shaft 44 so that the openings 50a
and 50b are arranged at equal intervals in the circumferential
direction of the outer circumferential surface.
[0065] One pair of passages 52a, 52a (see FIG. 14) extends through
the center shaft 44 from the one pair of the openings 50a
corresponding to the one pair of the chambers 48a in the internal
space 41 of the housing 43 to the one end portion of the center
shaft 44, which is positioned upward in the center shaft 44. The
one pair of the passages 52a, 52a is opened in an end surface of
the one end portion. As shown in FIGS. 10, 12, and 13, the paired
passages 52a, 52a can be integrated into one passage 52a in the
center shaft 44 before they reach the one end portion. As shown in
FIGS. 1 and 12, the opening of the integrated passage 52a in the
end surface of the one end portion of the center shaft 44 is
connected to the pipe for the low-pressure brine LPB, which extends
from the power recovery device 24 (in this embodiment, 24').
[0066] Another pair of passages 52b, 52b (see FIG. 14) extends
through the center shaft 44 from the other pair of the openings
50b, 50b corresponding to the other pair of the chambers 48b, 48b
in the internal space 41 of the housing 43 to the one end portion
of the center shaft 44, which is positioned upward in the center
shaft 44. The other pair of the passages 52b, 52b is opened in the
end surface of the one end portion. As shown in FIGS. 10, 12, and
13, the paired passages 52b can be integrated into one passage 52b
in the center shaft 44 before they reach the one end portion. In
this embodiment, the paired passages 52b, 52b are integrated into
the one passage 52b to be concentric with the above described one
integrated passage 52a in the end surface of the one end portion of
the center shaft 44. As shown in FIGS. 1 and 12, the opening of the
integrated passage 52b in the end surface of the one end portion of
the center shaft 44 is connected to the pipe for the high-pressure
brine HPB, which extends from the reverse osmosis membrane unit 18
to the power recovery device 24 (in this embodiment, 24').
[0067] A through hole 43d is formed in a center of a bottom surface
of the internal space 41 of the housing 43 (i.e., a bottom surface
of the case 42a) of this embodiment, and an output shaft 54a of a
motor 54 is rotatably and liquid-tightly inserted into the through
hole 43d. This rotatable and liquid-tight insertion of the output
shaft 54a of the motor 54 can be performed by, e.g., interposing a
well-known annular sealing member such as an O-ring or oil seal
between the inner circumferential surface of the through hole 43d
and the outer circumferential surface of the output shaft 54a of
the motor 54.
[0068] A protruding end of the output shaft 54a of the motor 54
inserted into the through hole 43d is concentrically fixed to an
out side surface a bottom wall of the blind hole 46a in the center
of the rotary member 46 in the internal space 41 of the housing
43.
[0069] An operation of the power recovery device 24' described
above with reference to FIGS. 10-14 will now be explained with
reference to FIG. 10.
[0070] As shown in FIG. 12, the high-pressure brine HPB supplied
from the reverse osmosis membrane unit 18 shown in FIG. 1 to the
power recovery device 24 (in this embodiment, 24') reaches the
other pair of the openings 50b, 50b in the outer circumferential
surface of the other end portion of the center shaft 44 through the
passage 52b opened in the end surface of the upwardly one end
portion of the center shaft 44 of the power recovery device 24',
and flows into several channels 46d inner ends of which are exposed
to the other pair of the openings 50b, 50b, among the plurality of
channels 46d of the rotary member 46. Meanwhile, as shown in FIG.
10, the low-pressure feed LPF supplied from the preprocessing unit
10 shown in FIG. 1 to the power recovery device 24 (in this
embodiment, 24') through the water supply pump 12 and safety filter
14 flows into the one pair of the chambers 48a, 48a of the case 43a
of the housing 43 of the power recovery device 24'. The
low-pressure feed LPF flowed into the one pair of the chambers 48a,
48a pushes parts of the outer circumferential surface of the rotary
member 46, which are exposed in the one pair of the chambers 48a,
48a, in a predetermined circumferential direction of the outer
circumferential surface of the rotary member 46. As a result, the
low-pressure feed LPF in the one pair of the chambers 48a, 48a
flows into several channels 46d, outer ends of which are exposed in
the one pair of the chambers 48a, 48a among the plurality of
channels 46d of the rotary member 46, and pushes side surfaces of
the several channels 46d. A part of the energy of the low-pressure
feed LPF is consumed to rotate the rotary member 46 in a
predetermined direction R.
[0071] As the rotary member 46 rotates, the low-pressure feed LPF
in the channels 46d is held in the channels 46d between the one
pair of the chambers 48a, 48a and the other pair of the chambers
48b, 48b and between the one pair of the openings 50a, 50a and the
other pair of the openings 50b, 50b of the center shaft 44. After
that, when the channels 46d holding the low-pressure feed LPF
oppose the other pair of the chambers 48b, 48b and the other pair
of the openings 50b, 50b of the center shaft 44, the low-pressure
feed LPF held in the channels 46d is pushed out from the channels
46d into the other pair of the chambers 48b, 48b by the
high-pressure brine HPB flowed from the other pair of the openings
50b, 50b into the channels 46d holding the low-pressure feed LPF.
During this action, the pressure energy of the high-pressure brine
HPB flowed from the openings 50b, 50b into the channels 46d is
given to the low-pressure feed LPF held in the channels 46d. As a
result of this, the low-pressure feed LPF held in the channels 46d
becomes the high-pressure feed HPF and is pushed into the other
pair of the chambers 48b, 48b.
[0072] The high-pressure brine HPB flowed into the channels 46d
from the other pair of the openings 50b, 50b gives its pressure
energy to the low-pressure feed LPF in the channels 46d and becomes
into the low-pressure brine LPB because the pressure energy of the
high-pressure brine HPB is largely decreased or eliminated. After
that, further rotation of the rotary member 46 causes the
low-pressure brine LPB to be held in the channels 46d between the
other pair of the chambers 48b and the one pair of the chambers
48a, 48a and between the other pair of the openings 50b, 50b and
the one pair of the openings 50a, 50a of the center shaft 44. And,
when the channels 46d holding the low-pressure brine LPB oppose the
one pair of the chambers 48a, 48a and the one pair of the openings
50a, 50a of the center shaft 44, the low-pressure brine LPB held in
the channels 46d is discharged out from the power recovery device
24 (in this embodiment, 24') through the one pair of the openings
50a, 50a and the one pair of the passages 52a, 52a corresponding to
the one pair of the openings 50a, 50a by the low-pressure feed LPF
flowed into the passages 46d from the one pair of the chambers 48a,
48a.
[0073] As shown in FIGS. 10 and 1, the high-pressure feed HPF in
the other pair of the chambers 48b, 48b is led through the pipe
from the power recovery device 24 (in this embodiment, 24') to the
pipe between the pressure raising unit 16 and the reverse osmosis
membrane unit 18. In the latter pipe, the high-pressure feed HPF is
added to the high-pressure preprocessed seawater HPSW flowing from
the pressure raising unit 16 toward the reverse osmosis membrane
unit 18, and flows together with the high-pressure preprocessed
seawater HPSW toward the reverse osmosis membrane unit 18.
[0074] As a result of this, if an amount of the fresh water FW
extracted in the reverse osmosis membrane unit 18 per unit time is
constant, it is possible to reduce an amount of the high-pressure
preprocessed seawater HPSW to be supplied from the pressure raising
unit 16 toward the reverse osmosis membrane unit 18 per unit time.
This makes it possible to reduce an amount of the energy, i.e., a
power necessary to operate the seawater desalination apparatus as a
kind of the liquid processing apparatus using the power recovery
device 24 (in this embodiment, 24').
[0075] Note that, in this embodiment, the rotation of the rotary
member 46 in the internal space 41 of the housing 43 can be
controlled by using the motor 54.
[0076] That is, the amount of the energy to be given to the
high-pressure feed HPF which is led through the pipe from the power
recovery device 24' of this embodiment to the pipe between the
pressure raising unit 16 and the reverse osmosis membrane unit 18,
by the rotation of the rotary member 46 of the power recovery
device 24', can be controlled regardless of a value of a rotation
force to be given to the rotary member 46 by the low-pressure feed
LPF supplied to the power recovery device 24'.
[0077] In the power recovery device 24' of this embodiment, the one
set of the two pairs of the chambers 48a and 48b are provided to be
divided from each other in the internal space 41 of the case 43a of
the housing 43, and the same low-pressure feed LPF is supplied to
the one pair of the cambers 48a, 48a symmetrically arranged with
respect to the center shaft 44, and at the same time the same
high-pressure brine HPB is supplied toward the other pair of the
chambers 48b, 48b symmetrically arranged with respect to the center
shaft 34. Accordingly, a force loaded on the case 43a of the
housing 43 and a force loaded on the rotary member 46 accommodated
in the internal space 41 of the case 43a so as to be rotatable on
the outer circumferential surface of the center shaft 44, by the
low-pressure feed LPF in the one pair of the chambers 48a, 48a, are
canceled in the radial direction of the center shaft 44, and also a
force loaded on the case 43a and a force loaded on the rotary
member 46, by the high-pressure brine HPB in the other pair of the
chambers 48b, 48b, are canceled in the radial direction of the
center shaft 44.
[0078] Further, a mixture of the low-pressure brine LPB and
high-pressure brine HPB, entered into a gap between the outer
circumferential surface of the other end portion of the center
shaft 44 and the inner circumferential surface 46b of the blind
hole 46a of the rotary member 46 functions as a radial dynamic
pressure bearing between the outer circumferential surface of the
other end portion of the center shaft 44 and the inner
circumferential surface 46b of the blind hole 46a of the rotary
member 46 with a rotation of the rotary member 46 on the outer
circumferential surface of the center shaft 44. Also, a mixture of
the low-pressure feed LPF and high-pressure feed HPF, entered into
gaps between the outer circumferential surface 46c of the rotary
member 46 and regions of an inner circumferential surface of the
internal space 41 of the case 43a of the housing 43, the inner
circumferential surface of the internal space 41 opposing the outer
circumferential surface 46c of the rotary member 46 and the regions
excepting the one set of the two pairs of the chambers 48a and 48b,
functions as a radial dynamic pressure bearing between the outer
circumferential surface 46c of the rotary member 46 and the
above-mentioned regions of the inner circumferential surface of the
internal space 41 of the case 43a of the housing 43 with the
rotation of the rotary member 46 on the outer circumferential
surface of the center shaft 44.
[0079] Therefore, there is no need for an independent radial
bearing between the outer circumferential surface of the other end
portion of the center shaft 44 and the inner circumferential
surface 46b of the blind hole 46a of the rotary member 46, and it
is possible to simplify the structure of the power recovery device
24' of this embodiment and to reduce a manufacturing cost
thereof.
[0080] More further, a mixture of the low-pressure brine LPB and
high-pressure brine HPB and a mixture of the low-pressure feed LPF
and high-pressure feed HPF, both mixtures entered into a gap
between an inner surface of the lid 43b of the housing 43 and one
side surface of the rotary member 46, which opposes the
above-mentioned inner surface, in the internal space 41 of the case
43a of the housing 43, function as a thrust bearing between the
inner surface of the lid 43b and the one side surface of the rotary
member 46 with the rotation of the rotary member 46 on the outer
circumferential surface of the other end portion of the center
shaft 44. Simultaneously, the mixture of the low-pressure brine LPB
and high-pressure brine HPB, entered into a gap between the end
surface of the other end portion of the center shaft 44 and the
bottom surface of the blind hole 46a of the rotary member 46,
function as a thrust bearing between the end surface of the other
end portion of the center shaft 44 and the bottom surface of the
blind hole 46a of the rotary member 46 with the rotation of the
rotary member 46 on the outer circumferential surface of the other
end portion of the center shaft 44. Further, the mixture of the
low-pressure feed LPF and high-pressure feed HPF, entered into a
gap between the bottom surface of the internal space 41 of the case
43a of the housing 43 and the other side surface of the rotary
member 46, which opposes the above-mentioned bottom surface, in the
internal space 41 of the case 42a of the housing 43, functions as a
thrust bearing between the bottom surface of the internal space 41
of the case 43a and the other side surface of the rotary member 46
with the rotation with the rotation of the rotary member 46 on the
outer circumferential surface of the other end portion of the
center shaft 44.
[0081] Therefore, there is no need for independent thrust bearings
between the inner surface of the lid 43b and the one side surface
of the rotary member 46, between the end surface of the other end
portion of the center shaft 44, and between the bottom surface of
the internal space 41 of the case 43a and the other side surface of
the rotary member 46, and it is possible to simplify the structure
of the power recovery device 24' of this embodiment and to reduce
the manufacturing cost thereof.
[0082] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the inventions. Indeed, the novel
embodiments described herein may be embodied in a variety of other
forms;
[0083] furthermore, various omissions, substitutions and changes in
the form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
* * * * *